1. Somebody really ripped and muscular. Usu. male.
2. Used ironically to describe somebody extremely overweight. Popularized by an early episode of South Park in which Cartman drinks weight gain formula and gets really huge.
3. A cake made of meat. Almost always beef.

a grade A piece of beef, and a nice cake, together these two words mean only good things!
it is a common term for women to call men a beefcake when they think that the person in good looking or buff or someone who they are attracted to!